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Title: Psychoactive Drugs


1
Psychoactive Drugs
  • Dr. Kline
  • Part I

2
I.  How drugs are handled by the body?
  • 1.     Absorption into the body.
  •  2.     Distribution of the drug through the
    body, including the fetus, at time drug is taken.
  •  
  • 3.     Metabolism the detoxification of the
    drug by the body (liver). Most drugs are broken
    down into metabolites (by-products or waste) that
    no longer exert an effect.
  •  
  • 4.     Elimination of the drug, usually
    excreted through urine.
  •  

3
Six routes of drug entry into body
  • 1.     Orally (tablets, capsules, liquid)
  • 2.     Rectally (suppositories)
  • 3.     Intravenous (injected in liquid form
    through a needle into the skin)
  • 4.     Inhaled through the lungs (as gases,
    vapors, or particles)
  • 5.     Through skin (patches on skin)
  • 6.     Through mucous membranes (snorting or
    sniffing under tongue)
  •  

4
How drugs act on the system
  • The pharmacological, physiological, or behavioral
    effects induced by a drug follow their
    interaction with receptors.
  • This is called pharmacodynamics involves the
    mechanisms of drug action that occur at the
    molecular level.

5
Drugs produce effects by
  • binding to interacting with specialized
    receptors, located on the synapses of neurons.

6
What are receptors?
  • A receptor is a large molecule on the cells
    surface where endogenous compounds
    (neurotransmitters) induce their normal effects.
  • Usually only 1-2 neurotransmitters is specific
    enough to fit or bind to a specific receptor.

7
Binding to receptors
  • 1.    A drug that binds to a receptor normally
    occupied by a given transmitter can initiate a
    cellular response similar or identical to that
    exerted by the transmitter.
  • The drug mimics the action of the transmitter.
    Here, the drug is an agonist for that
    transmitter.  
  • 2.  A drug that binds to a receptor blocks the
    neurotransmitter from stimulating the cell is
    called an antagonist.

8
II. Dose-Response Relationships
  • A dose-response curve may be plotted as
  • the dose of a drug given as a function of the
    of people who show an effect at a given dosage.

9
Drug Effectiveness
  • The dose of a drug that produces the desired
    effect in 50 of subjects tested is called the
    ED50.
  • The lethal dose for 50 of subjects (animals) is
    called the LD50.
  • The ratio of the LD50 to the ED50 is used as an
    index of the relative safety of the drug is
    called the therapeutic index

10
III. Drugs
  • A. ALCOHOL (ethanol)
  • Alcohol is found in different concentrations
    in liquid
  • -12 in wine
  • -3.5-5 in beer
  • -40-50 in liquors
  • It is most often expressed as proof which is
    twice the percent concentration (i.e., 80 proof
    40 ethanol).

11
Alcohol absorption
  • Alcohol readily diffuses across all biological
    membranes is completely absorbed by the entire
    GI tract.
  • Alcohol usually takes 30-90 minutes to reach
    peak levels in the blood.
  • About 20 of a single dose of alcohol is
    absorbed directly via the stomach.
  • The remaining 80 is absorbed rapidly by the
    large intestine.

12
Alcohol metabolism
  • 85 by liver
  • 5-by lungs (can be detected by breath)
  • 15- broken down by stomach enzymes.
  • A full stomach reduces a persons blood alcohol
    level, because the enzymes have longer time to
    metabolize the alcohol.

13
Who has the higher blood alcohol level, men or
women?
  • Women!!!
  • 1.  Women --50 less gastric metabolism of
    alcohol, because they have lower levels of
    gastric enzymes.
  • 2.  Since men have greater ratio of muscle to fat
    than do women, alcohol is more diluted in their
    blood (fat has little blood supply in contrast to
    muscle).
  •  

14
What are the effects of alcohol?
  • 1. Physiological effects-
  • Slows Respiration (CNS depressant)
  • Sedative effects are additive when combined with
    other depressants (e.g., barbituates).
  • Dilates blood vessels in skin (decreases body
    temp blushing).
  • Lowers cholesterol (low doses) by lowering LDL
    increasing HDL.
  • May cause heart damage (high doses-5 drinks per
    day).
  • May cause liver damage (high doses over time)

15
2. Psychological effects
  • Behavioral disinhibition (low doses)
  • Euphoria (low to moderate doses)
  • Violent or irascible mood (moderate to high
    doses)
  • Memory, concentration, insight are impaired
  • Reaction time is impaired
  • Motor system is impaired (cerebellum)
  •  

16
How does alcohol produce its effects?
  • 1. Alcohol is a GABA agonist, it facilitates
    expression of GABA (inhibitory transmitter).
    Contributes to behavioral disinhibition, motor
    slowing.
  • 2. Alcohol inhibits glutamate (excitatory
    system). Receptors, which may cause cognitive
    effects of alcohol intoxication, such as slurred
    speech memory loss.
  • Alcohol increases levels of dopamine serotonin,
    likely providing both euphoric sedative
    effects.

17
B. MARIJUANA
  • Dried crushed leaves flowering tops of the
    hemp plant, Cannabis sativa.
  • Major ingredient-- delta-9-tetrahydrocannabinol
    (THC)
  • Marijuana has 2-5 THC
  • May be smoked, chewed, or eaten (in baked goods).

18
What are effects of marijuana?
  • 1. Physiological effects
  • Produces analgesia
  • Has antiemetic properties (decreases nausea
    vomiting)
  • Increased HR blood pressure
  • Dilated blood vessels in eyes (bloodshot eyes)
  • Sedative effects

19
2. Psychological effects
  • Shifts in emotion
  • Disrupted attention
  • Impaired STM
  • Altered sensory perception
  • Time distortions (time moves more slowly)
  • Motor activity impaired
  • Hallucinations (with heavy doses)
  • Panic (with heavy doses)

20
How does marijuana produce its effects?
  • We have cannabis receptors in the brain. These
    receptors are found in the
  • 1. basal ganglia (fine motor system)
  • 2. cerebellum
  • 3. cortex (especially the frontal lobe)
  • 4. hippocampus
  • We dont have any cannabis receptors in the
    brainstem. THC does not affect basal body
    functions.

21
Do we have a transmitter substance like THC in
our brains?
  • Yes!!! We have anandamide which binds to
    cannabinoid receptors produces cannabinoid-like
    pharmacological effects.

22
C. HALLUCINOGENS
  • 1. LSD
  • First synthesized in 1938, as a compound of ergot
    (a fungus that grows on rye) by Hoffman.
  • Hoffman accidentally ingested the drug noticed
    its unusual effects.
  • During 1950s, LSD was used as a model for
    examining treating psychosis was also used in
    therapy.

23
LSD administration
  • Is taken orally.
  • ED50 is 25 micrograms to 300 micrograms.
  • Usually is found on sugar cubes, stamps, candy
    dots
  • Is absorbed within 1 hour peaks in 3 hours.
  • Duration 6-8 hours.

24
What are the effects of LSD?
  • 1. Physiological Effects
  • Slight increase in body temperature
  • pupil dilation
  • slightly increased HR blood pressure
  • dizziness nausea

25
2. Psychological Effects
  • 1.     Altered perception, thinking, emotion,
    arousal
  • 2.     time distortions (slowed)
  • 3.     Intense visual auditory hallucinations
    (trasers)
  • 4.     Cross-sensing (hearing colors seeing
    sounds)
  • 5.     emotions shift rapidly (happiness to pit
    of despair)
  • 6.     tension anxiety make lead to panic
  • 7.     psychotic experience

26
How does LSD produce its effects?
  • LSD exerts its effects by interacting with
    serotonin receptors (5-HT receptors).
  • Most researchers argue its a serotonin agonist.

27
2. MESCALINE
  • Comes from the crown or button of the peyote
    cactus.
  • The crown is dried into a hard brown disk that
    softens when ingested.
  • Is absorbed in 1-2 hours.
  • Effects occur between 3.5 4 hours after
    ingestion. Vivid hallucinations most salient.
  • --trip is long (10 hours)
  • Right frontal activity seems to be high in people
    on mescaline. Agonistic for norepinephine
    serotonin.

28
3. PSILOCYBIN
  • Found in mushrooms (genera Psilocybe).
  • Mushrooms are eaten raw.
  • mushrooms grow through out world, including
    northwestern US.
  • It peaks in about 2 hours, effects
  • last 6-10 hours.

29
How does it produce its effects?
  • It appears to exert its effects as a serotonin
    agonist that stimulates 5-HT receptors especially
    in the frontal areas.

30
4. MYRISTIN ELEMICIN
  • Are agents found in nutmeg mace, two common
    household spices.
  • ED50--1-2 teaspoonsusually brewed in tea
  • Within 2-5 hours, you get symptoms similar to LSD
    (euphoria, visual hallucinations, psychosis,
    etc.)
  • However, most people experience vomiting, nausea,
    tremors prior to the trip making it a one
    time event for many.

31
D. STIMULANTS
  • In general these drugs
  • increase behavioral activity
  • elevate mood
  • increase alertness
  • allay sleep
  • increase brains metabolic neuronal activity.

32
1. COCAINE
  • Comes from the coca plant (Erythroxylon coca)
    found in South America.
  • The active alkaloid in E. coca was isolated in
    1855, purified in 1860, named cocaine.
  • In late 1800s, cocaine was used as an anesthetic
    (spinal, local), was added to medicines
    Coca-Cola.
  • It was banned from use in medicines beverages
    in 1914 in the Harrison Narcotic Act.

33
COCAINE (history)
  • By 1930s, amphetamines replaced the popularity of
    cocaine.
  • 1960s- cocaine makes a comeback when amphetamines
    become pricey.
  • 70s-80s cocaine becomes chic with jetset.
  • cheap crack cocaine becomes hit in poor
    areas.
  •  

34
Forms of cocaine
  • Cocaine can be snorted, smoked, taken orally, or
    injected intravenously.
  • Powdered cocaine (cocaine hydrochloride) 25 mg
    per line.
  • Crack cocaine- (250 mg-1 gm) per smoke.

35
Physical Effects
  • Vasoconstrictor
  • Increases norepinephrine dopamine
  • Tachycardia
  • Stroke, seizure, heart attack
  • Increased blood pressure
  • Local anesthetic

36
Psychological Effects
  • Euphoria
  • Elevated mood
  • Agitation
  • Flight-of-ideas
  • Grandiose thoughts

37
How does it produce its effects?
  • Cocaine blocks reuptake of dopamine,
    norepinephrine, serotonin, thereby increasing
    them in the CNS.
  • Increasing dopamine levels in dopaminergic reward
    system results in euphoric/addictive effects of
    drug.

38
2. AMPHETAMINES- Effects
  • Vasoconstriction
  • Hypertension
  • Tachycardia
  • Increased motor activity
  • Loss of appetite
  • Restlessness/tremors 
  • hallucinations (amphetamine psychosis)
  • Paranoid delusions

39
Amphetamines-today
  • 1.  Therapeutic use in the treatment of
    narcolepsy ADHD.
  • 2.  To treat compulsive misuse of methamphetamine
    (amphetamine derivative).

40
How do amphetamines cause their effects?
  • They cause release of norepinephrine dopamine
    from presynaptic storage sites in nerve
    terminals.
  • Peripheral NS activity --increased norepinephrine
     

41
ICE- form of methamphetamine
  • Was originally used to treat ADHD, not mostly a
    an illegal street drug.
  • Street names of drug Speed, crystal, crank, go,
    ICE.
  • Methamphetamine--orally, by IV injection,
    snorted. The base form (ICE) can be smoked.
  • ICE-methamphetamine, crack-cocaine. Its the
    free-base, smokable form of the parent compound.

42
NONAMPHETAMINE BEHAVIORAL STIMULANTS
  • Does not have the same nucleus structure of
    amphetamines, but shares same action of
    increasing SNS activation.
  • One of the most common of these is
  • Methylphenidate (Ritalin)

43
Methylphenidate (Ritalin)
  • Has a short half life (2-4 hours).
  • Concerta--A new sustained-release formulation of
    methylphenidate--taken in the early AM, it is
    good through the day.
  • Is much more expensive than regular Ritalin.

44
How does Ritalin exert its effects?
  • Thought to increase norepinephrine dopamine, by
    blocking reuptake in the presynaptic neuron.
    Also stimulates the release dopamine.
  • Once thought to exert its behavioral effects
    (calming) via increased dopamine, it is now
    thought that effects may be result of increased
    serotonin activity (or balance of both).

45
3. CAFFEINE
  • The most common psychoactive drug in world.
  • Consumed -80 of adult population.
  • 1 cup of coffee---50-150 mg of caffeine.
  • Caffeine content of chocolate--25 milligrams per
    ounce.
  • Average intake 3-5 cups of coffee every day.

46
Absorption
  • Significant blood levels of caffeine are reached
    in 30 to 45 min with complete absorption in 90
    min.
  • Peaks in about 2 hrs decreases thereafter.
  • The half-life is about 3.5 to 5 hours in most
    adults.

47
Effects
  •  
  • tachycardia
  • Increased Blood pressure
  • Vasoconstriction
  • Diurectic
  • Increased mental activity alertness
  • Increased wakefulness
  • Agitation
  • Tremors
  • Anxiety
  • Insomnia

48
 
  • HOW DOES CAFFEINE EXERT ITS EFFECTS?
  • Caffeine exerts its effects by blocking adenosine
    receptors.
  • Adenosine is a neuromodulator that influences the
    release of several neurotransmitters in the CNS.
  • It appears to exert sedative, depressant,
    anticonsulsant actions. Thus, blocking adenosine
    causes anxiogenic effects.

49
E. OPIATES
  • A group of addictive sedatives that in
  • moderate doses relieve pain induce sleep.
  • The original principle opiate was opium, which is
    extracted from poppy seeds of the poppy plant
    (papaver somniferum).
  • The psychoactive ingredient in opium is morphine,
    named for Morpheusthe Greek God of dreams.
  • Two drugs are found in the exudate of the poppy
    morphine codeine.

50
OPIATES-History
  • Opium--has been used for thousands of years to
    produce euphoria, analgesia, sleep, relief from
    diarrhea cough.
  • Ancient Greece Rome-- through the 16th-
    17th-centuries, opiums medicinal recreational
    uses were well established.
  • A mixture of opium and alcohol, called laudanum,
    was used to treat practically every disease known
    during the 1800s.

51
OPIATES-History
  • During the civil war, opium addiction was a
    widespread problem.
  • By 1914, the Harrison Narcotic Act was passed and
    the use of most opioid products was controlled.

52
Opiates vs. Opioids
  • Opiate-- is a drug that is extracted from the
    exudates of the poppy.
  • E.g., morphine and codeine.
  • An opioid is any exogenous drug (natural or
    synthetic) that binds to an opiate receptor
    produces agonist or morphine-like effects.
  • E.g., heroin

53
Endorpins (morphine-within)
  •  Endorphins --any endogenous substance (naturally
    occurring in the body) that exhibits
    pharmacological properties of morphine.
  • We have 3 families of endorphinsenkephalins,
    dynorphins, beta-endorphins.

54
MORPHINE
  • Is still the most potent pain reliever available
    (no other drug has its clinical effectiveness).
  • Is administered orally, rectally, or by
    injection. Absorption is slow only 20 of the
    drug reaches the CNS.
  • Is broken down by liver produces metabolites
    (morphine t-glucoronide) that are 10 to 20-fold
    more potent that morphine itself. These continue
    exerting analgesic effects.
  • Morphines half-life 3 to 5 hours.

55
MORPHINE-DRUG TESTING
  • For 2 to 4 days following opiate use, urine
    screening tests can be used to detect codeine
    morphine as well as their metabolites.
  • Heroin use can be tested for indirectly. Heroin
    is metabolized to morphine also often contains
    acetylcodeine (metabolized form of codeine).
  • Although the tests cannot accurately determine
    which drug (heroin, codeine, morphine) was
    present.

56
WHAT ARE EFFECTS OF MORPHINE?
  • Analgesia
  • Relaxation
  • Euphoria
  • Sedation
  • Sense of transquility
  • Reduced anxiety
  • Respiratory depression
  • Cough suppression

57
HOW DOES MORPHINE EXERT ITS EFFECTS?
  • Morphine, like other opiates opioids, exert its
    effects by stimulating opiate receptors widely
    distributed through the CNS (brain, brain stem,
    spinal cord).

58
 CODEINE
  • Is usually combined with aspirin or acetaminophen
    for the relief of mild to moderate pain.
  • Half-life--3 to 4 hours.
  • Codeine is metabolized by hepatic cytochrome
    CYP2D6 enzymes to morphine, many of its effects
    may be the result of morphine actions.
  • Using serotonin-specific antidepressants can
    block the pain relief of codeine, because they
    block the conversion of codeine to morphine.

59
HEROIN (diacetylmorphine)
  • Is produced by a slight modification of the
    chemical structure of morphine.
  • It cross the blood-brain barrier very rapidly,
    leading to an intense rush when it is either
    smoked or injected intravenously.
  • It is metabolized to monoacetylmorphine
    morphine.
  • Clinical use of heroin is legal in Great Britain
    Canada.

60
F. ANTIDEPRESSANTS
  • A broad class of drugs used to treat depression.
  • What is depression???
  • A state of great sadness characterized by
    feelings of despair, worthlessness, hopelessness,
    withdrawal from other.
  • Its the common cold of psychopathologyweve
    all had symptoms at some point.

61
Major depression DSM diagnosis made if
  • Person has 5 of the following symptoms (next
    slide) for at least 2 weeks.
  • Depressed mood or loss of interest pleasure in
    enjoyable activities (anhedonia) must be included
    in symptoms.

62
Symptoms of major depression
  • 1. Depressed mood.
  • 2. Loss of interest and pleasure.
  • 3. Significant weight loss or weight gain.
  • 4. Difficulty in sleeping-Insomnia or
  • hypersomnia.
  • 5. Shift in activity level, psychomotor
    retardation, or agitated.
  • 6. Fatigue or loss of energy.
  • 7. Negative self-concept.
  • 8. Difficulty concentrating.
  • 9. Recurrent thoughts of death or suicide.

63
1. Tricyclics
  • E.g., imipramine (Tofranil) and amitriptyline
    (Elavil).
  • These prevent reuptake of both norepinephrine
    serotonin by the presynaptic neuron.
  • 2. Monoamine oxidase (MAO) inhibitors -
    tranylcypromine (Parnate)
  • Keeps enzyme monoamine oxidase from
    deactivating neurotransmitters, thereby
    increasing the levels of both serotonin and
    norepinephrine.

64
3. Selective serotonin reuptake inhibitors
(SSRIs) fluoxetine (Prozac) sertraline
(Zoloft). 
  • Selectively blocks reuptake of serotonin.
  • Efficacy of all three classes of drugs about the
    same (50-70 effective).
  • Side effects fewer in SSRIs. Tricyclics can be
    dangerous.
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